Just a quick question over something that's been puzzling me a bit. Hay means 'there is' or 'there are', but in the verb tables for haber in my dictionary it doesn't list hay at all. Why is not ha ? How do you arrive at hay ? Does this happen with any other verbs ?

Hi cronos,
'hay' means both "There is" and "There are". It is an impersonal form of verb 'haber' (to show the existence of objects, people, beings,...), so that's why it is not affected by gender or number, and we use 'hay' instead of 'ha'*

Hay un gato sobre la mesa -----> There is a cat on the tableHay una ardilla cerca del árbol -----> There is a squirrel near the tree

Hay tres manzanas en la heladera -----> There are three apples in the¡Hay mucha gente aquí! ----> There are too many people here¡Hay muchas personas aquí! ----> There are too many people here

But it is affected by time.Hubo un terremoto ---> There was an earthquakeHubo varios terremotos ---> There were several earthquakesSi hubiese más árboles, habría menos polución del aire---> If there was more trees, there would be less air pollution